ML19296B768
| ML19296B768 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 02/14/1980 |
| From: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8002210486 | |
| Download: ML19296B768 (2) | |
Text
st CONNECTICUT YANKEE ATOMIC POWER COMPANY BERLIN, CONNECTICUT P O. BOX 270 H ARTFORD. CONNECTICUT 04101 Tateemons 203 666-6911 February 14, 1980 Docket No. 50-213 Darrell G. Eisenhut, Acting Director Division of Operating Reactors Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Gentlanen:
lladdam Neck Plant Information on Spurious PORV Operation In response to a February 7,1980 verbal request from the NRC Staff, Co. nect'. cut Yankee Atomic Power Cmapany (CYAPCO) hereby submits the following information about the spurious opening of a power-operated relief valve (PORV) on the pressurizer at the Haddam Neck Plant.
At approximately 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on February 4,1980, alarms in the control room indicated that a pressurizer PORV had opened. Multiple alarmed parameters were reviewed including reactor pressure, pressurizer relief tank temperature and pressure, pressurizer relief valve position switch, and pressurizer relief valve acoustic monitor.
Each of these alarms is both visual and audible. The PORV and associated block valve were remote-manually closed within approximately ten (10) seconds.
It should be noted that the acoustic monitor, which was installed as a result of the Short-Term Lessons-Learned requirements (ltem 2.1.3.a),
f acilitated the rapid identification and resolution of the incident.
A review of the visual and recorded data associated with the incident revealed that reactor pressure dropped from 2020 psig to approximately 1992 psig, pressure in the relief tank rose to approximately 15 pounds, and temperature in the line to the relief tank exceeded the 165'F alarm point. Technical Specifications require that, at 100% power, the reactor coolant system (RCS) pressure be maintained at or above 2000 psig.
If pressure falls below 2000 psig, it must be restored to this limit within two hours, and the incident must be reported in 30 days. RCS pressure was restored to greater than 2000 psig within two (2) minutes.
An investigation into what caused the PORV to open was started immediately. The breaker supplying power to the block valve was opened, essentially locking the valve in the closed position.
The second PORV and block valves and a third block 8002210
J valve remained in service.
The subject PORV was monitored for a week to detect any more spurious movement or perturbations, and none were observed.
CYAPCO has concluded that the spurious opening was most probably caused by dirty contacts which caused a short-circuit in the PORV operator. The block valve was reconfigured to its normal state on February 11, 1980.
We trust this information is responsive to the Staff's request.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY
'l,
6:!s?!!
W. G.(founsil Vice President By:
W.'F.
Fee Vice President